Formation testing tools can measure formation pressures along a wellbore and can obtain formation fluid samples as well. Information from the pressures and samples can then help characterize the wellbore and can predict performance of the surrounding reservoirs. Formation testing tools can be conveyed downhole in a variety of ways, including wireline, drill string, or the like. In fact, formation testing tools disposed on drill collars of a drilling assembly evaluate newly drilled formations.
When used, the formation testing tool obtains formation pressures and reservoir fluids from desired locations or zones of interest in the wellbore. Because drilling mud is used during drilling, the formation testing tool first tests the obtained fluid to determine if it is free of mud filtrates. To do this, fluid samples can be directly analyzed with a variety of sensors, including optic devices, spectrometers, temperature sensors, pressure sensors, etc. Stored fluids can also be analyzed at the surface.
Tools, such as formation testing tools, used during drilling have limited capability to communicate with the surface. For this reason, controlling the tool by operators or surface equipment is often hindered by the lack of “real time” or limited communication between the downhole instrument and the surface. In the end, data quality may be compromised because of the inability to interact with the tool operation in a timely manner.
During a test operation, for example, pressure data collected on a drilling tool may not be communicated to the surface for multiple reasons, such as communication errors, poor signal to noise ratio, or by test design. Operators at the surface may not be able to monitor pressures in the tool's flowline in real time, and information from the drawdown and buildup of the pressure test cannot be viewed in real time at the surface. Thus, operators are unable to evaluate the quality of test measurements as they occur, and operators cannot abort a test or adjust the test's parameters during a formation test if needed.
Historically, operators have preprogrammed a fixed series of steps for the tool to perform. Once the tool is deployed, operators expect the tool to perform these steps as instructed. However, this procedure is neither efficient nor optimal due to the varying reservoir or formation properties. As long as the tool has sufficient processing capabilities, the downhole tool can use mathematical models to predict tool response and can then adjust operating parameters appropriately. Hence, there is a need for intelligent decision making in a downhole tool that replicates some of the decision-making capabilities that occur when an operator monitors and controls a formation tester in real time.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.